A DOG’S SENSES
PAWS AND JAWS
Again, it may seem obvious, but dogs have no opposable thumb. This means that they cannot pick up objects easily with their paws and, instead, will often use their mouths in situations where we would use our hands. Dogs do not hit people when upset but bite instead. They can learn to be very accurate with their mouths and, once experienced, will only rarely make unintentional contact with their teeth on human skin. In other words, if a dog snaps, but misses, he probably meant to! Dogs will also explore using their mouths in the same way as we will touch unusual objects. Since their mouths are full of teeth that can cause damage, this exploratory behaviour often gets them into trouble, particularly when they are puppies.
The need to explore new objects with their mouths can often get dogs into trouble.
Another striking difference between our species is that, as primates, we like to touch, hold, hug and cuddle to express affection. However, dogs rarely do this to each other unless they are fighting or mating. This accounts for why some dogs will bite when hugged or stroked, especially by children. In order for dogs to accept our loving behaviour, they need to become accustomed to it gradually, preferably during puppyhood.
A SMELLY FACT
A weak solution of salt is odourless to humans but dogs are able to detect as little as one teaspoonful in thirteen gallons of water.
SUPER SCENTING
One of the first things a dog will do in a new environment is to put his nose to the floor and sniff. A human in the same situation would look around. A dog when meeting another dog or a person will, characteristically, sniff them, sometimes in the most embarrassing, but smelliest, places. A human (fortunately!) will just look. Both are gathering information about their world, but the way in which they do it illustrates one of the most important differences between them. We live in a very visual world, whereas dogs live in a very smelly one.
Their sense of smell is incredible by our standards. Not only do they have many more cells in their nose for detecting different smells (the area used for smell detection is fourteen times the size of ours), but these cells are of better quality and the part of their brain that receives the information is considerably more developed. This allows dogs to detect and identify a much wider variety of scents at much lower concentrations.
Dogs gather a lot of information by sniffing at places in a territory which have been marked by other dogs.
Smells on the ground need careful investigation.
Using this ability enables them to acquire much more information in one sniff than we can ever imagine. Going for a walk and sniffing the scents left behind by other dogs must be like watching a video of all those who have passed by in the past few days. Information such as sex, health and social standing may be passed on through urine and faeces. This allows most male dogs, and some females, to advertise their presence and status by marking every available lamppost and clump of grass.
Although we cannot even begin to understand what it is like to be able to detect odours in the same way as our dogs do, knowing that they live in a different sensory world can help us to understand them better. It helps to explain some of their peculiar habits, such as sniffing everything they come into contact with, kicking up earth with their back hind legs after going to the toilet (they have scent glands in between their pads), and rolling in substances that we would rather they did not.
SCENT CAMOUFLAGE
Rolling in substances with a very strong scent has never been fully explained. It is likely that it is a remnant of the days when dogs’ ancestors needed to camouflage their own scent to be more like that of their environment in order to be more successful when out hunting.
EMPLOYING A DOG’S SUPERIOR SENSES
Man has utilized the dog’s incredible sense of smell in a variety of ways. To detect drugs, explosives, to find lost people, to track criminals, to find buried survivors after earthquakes or avalanches, to track animals to be hunted, or, more recently, to sniff out dry rot and termites in buildings, to find human bodies lost in water or to detect skin cancers and other diseases. In such exercises, dogs are better than any machine, having a better publicity value, being more accurate, more reliable, cheaper, and more fun!
SEEING THINGS DIFFERENTLY
Dogs have a greater field of vision than humans. This enables them to see things to the rear and sides. The amount of overlap (shaded area) will determine how well the animal can judge distances.
A human has a field of vision of about 100 degrees.
A whippet’s field of vision is about 200 degrees.
Dogs that have been bred to look more like us, such as the King Charles Spaniel, with forward-facing eyes, have a reduced field of vision.
Long-coated breeds with hair that hangs over their eyes will have their field of vision greatly reduced. It is best to clip it or tie it back so that they can see properly.
SENSITIVE SIGHT
Dogs can see less well than humans. They can see colours but not as well as we can, and they cannot differentiate easily between certain colours, such as red and green. A dog looking for a red ball, for example, on green grass is more likely to be using his nose than his eyes.
They do, however, see better than us when less light is available. A reflective layer at the back of their eyes allows them to make better use of the light entering the eyes by trapping and reusing it. This is why their eyes shine eerily when they are caught in car headlights or a torch beam.
While we are able to make out static shapes easily and can quickly differentiate between two objects, dogs see things better as soon as they move. They can detect movement on a very small scale, helping them to be efficient hunters. In our world, it enables them to notice subtle body movements, which allow them to detect, a fraction of a second before we have said anything, that we are about to take them for a walk.
IMPRESSIVE HEARING
Dogs can hear better than we can. Firstly, they hear sounds more acutely. For example, a sound that can just be heard by a person 100 metres away, can be heard by a dog for up to 450 metres. Secondly, dogs can hear sounds of a higher frequency. Our range is up to about 20 kHz whereas dogs can hear sounds up to at least 35 kHz, allowing them to hear in the ultrasonic range. They also seem to be able to discriminate between two sounds that appear the same to us. It is probably this sense more than any other that has led people to believe that dogs have a ‘sixth’ sense. Because of their superior hearing, for example, dogs may become aware of the arrival of their owner long before a person sitting in the same room. A dog can hear things that we cannot, such as a ‘silent’ dog whistle, and may alert us to the presence of intruders or other noises in the environment long before we have heard anything.
SOUND SENSITIVITY
Dogs that were once used for herding, such as Collies, have very sensitive hearing and, as a result, are more likely to find it difficult to live in very noisy environments and are more prone than other dogs to developing noise phobias.
Dogs with long, fluffy ears, such as Cocker Spaniels, are likely to be less good at sound detection and location.
MOVABLE EARS
Dogs are able to pinpoint the location of a sound source more accurately than us. This is achieved by having ears that can be manoeuvred into a position that allows them to catch sound more efficiently.
DIFFERENT METHODS OF COMMUNICATION
Everyday communication between adult dogs relies mostly on body posture and scent exchange with very little in the way of vocalization. In comparison, we rely very heavily on the spoken (or written) word and only use body signals and scent in very subtle and secondary ways.
BODY LANGUAGE V. SPOKEN WORD
Knowing no better, dogs will assume that our methods of communication are similar to their own and will attempt to communicate using body postures and signals. Owners need to know what to look for so that they do not miss these vital signs from their pets.
In addition, dogs will also watch our body language to try to find out what we want them to do. This is why dogs learn hand/arm signals so much more quickly than they learn spoken commands. Pointing out the direction you want your dog to take, using an obvious arm and hand movement, is surprisingly effective, and especially so once he has become familiar with the signal. If your dog, for example, has just brought a recently unearthed bone in from the garden and is about to drop it on the carpet, shouting at him to go out may not be effective. Asking him to go out, leading the way and pointing out the direction you intend him to take with a clear hand and arm movement, will give him a much more obvious message about the action you require him to take.
PLAYBOW
The universal invitation to play. A sudden drop into this position usually results in a frantic bout of tag between two playful dogs. If directed at a human, the dog is asking if you would like to play a game.
The playbow is an obvious invitation to play.
FEARFUL DOG
Frightened dogs will have a lot of their weight on their back legs ready to run. Their head is held high ready for a defensive bite if necessary. They hold their tail low or tucked in, ears drawn back but not pinned flat against the head. They will often pant in short, sharp breaths and may yawn a lot. In extreme cases, or if the dog is afraid for too long, they may begin to shake or tremble. The whites of their eyes can be seen as their eyes are held as wide open as possible. The pupils are often wide open and consequently the eyes may have a reddish tinge to them. If the eyes appear red and glassy, the dog is very fearful and should be approached with caution as he may well bite in self defence. The hair along the back of the neck (the hackles) and along the spine may also be raised, especially if he is fearful of other dogs. These make a dog look larger than he really is and help to reduce the chances of him being attacked.
This dog’s tail is lowered and his ears are drawn back in a fearful posture.
Dogs that are anxious but not yet very fearful will exhibit some or all of these signs in varying degrees. Watching for subtle clues that your dog is ill-at-ease can help you to take the appropriate action sooner rather than later and may help to prevent your dog from becoming scared or aggressive.
HAPPY DOG
A dog that is pleased to see you will wag his tail, sometimes the rear half of his body as well, press his ears back to the sides of his head and pull the corners of his mouth back in greeting.
Happy dogs appear relaxed and their bodies will be soft and not tense. They will eat readily and will be happy to play games and be handled. A pet dog should be relaxed, calm and happy most of the time.